Option 1 : Buying
cost = $560,615.26 I'll round off to $560,615
Deposit = 0.20*$560615 = $112,123 = $112,000 (roounded to the nearest thousand - paid in cash)
A= Amount borrowed = $560615 - $112000 = $448,615
Interest on loan = 6.5%pa = 0.065pa :
i = 0.065/12 = 0.0051666666666 per month
R = Regular payment = $3032.80 per month
The time to repay the loan n must be determined.
$$\boxed{ \mbox{Present value of an ordinary annuity }\qquad
A=R\times\frac{1-(1+i)^{-n}}{i}}$$
$$\begin{array}{rll}
A&=&R\times\frac{1-(1+i)^{-n}}{i}\\\\
448615&=&3032.80\times\frac{1-1.005416666666666^{-n}}{0.005416666666666}\\\\
\frac{448615\times 0.005416666666666}{3032.80}&=& 1-1.00516666666666^{-n}\\\\
\dfrac{448615\times 0.005416666666666}{3032.80}-1&=& -1.00516666666666^{-n}\\\\
-0.198760908&=& -1.005416666666666^{-n}\\\\
0.198760908&=& 1.005416666666666^{-n}\\\\
log(0.198760908)&=& log(1.005416666666666^{-n})\\\\
log(0.198760908)&=& -n*log(1.005416666666666)\\\\
\frac{log(0.198760908)}{log(1.005416666666666)}&=&-n\\\\
n&=&\frac{-log(0.198760908)}{log(1.005416666666666)} \\\\
n&=&299.08\;months \\\\
Loan\; period&=&25\;years\\
\end{array}$$
So now you need to go backwards to work out how much is owing on the house after 3 years.
22 years of the loan is left = 22*12 = 264 months
$$\begin{array}{rll}
A&=&R\times\frac{1-(1+i)^{-n}}{i}\\\\
A&=&3032.80\times\frac{1-(1.00541666666666)^{-264}}{0.00541666666666}\\\\
A&=&\$425,394\\\\
\end{array}$$
Equity after 3 years without considering appreciation = $560,651 - $425,394 = $135,221
Equity after 3 years considering appreciation = $135,221 * 1.0773 = $168,923
Costs without any adjustments = $12000
Balance after 3 years = $168,923-$12000 = $156,923